Dolby Laboratories DP564 - Manual (Page 73)

DP564 Multichannel Audio Decoder Appendix A: Metadata
A-3
transparent to consumers, certain parameters affect the output of a home decoder, like
when downmixing for a specific speaker configuration, or when the consumer
chooses Dynamic Range Control to avoid disturbing family and neighbors.
Figure A-1 shows a 5.1 + 2 Program Config consisting of a 5.1-channel program and
a two-channel Secondary Audio Program (SAP).
Program Source
5.1-Channel
Program
Two-Channel
(Stereo) Program
DP570
Multichannel Audio
Tool
in 5.1+2 Program Config
DP571
Dolby E Encoder
in 5.1+2 Program Config
Multichannel
Monitor System
L/R
C/LFE
Ls/Rs
Lt/Rt
The Dolby E bitstream
contains both the 5.1- and
two-channel programs’
encoded audio, and each
program's metadata.
The Dolby Digital bitstream
contains a single program’s
encoded audio and
corresponding metadata.
DP572
Dolby E Decoder
Metadata
Decoded Dolby E bitstream
delivers both the 5.1- and
two-channel programs’
encoded audio along with
corresponding metadata.
DP569
Dolby Digital Encoder
SAP or Visual
Descriptive
Broadcast
Cable, Satellite,
or Terrestrial
Consumer
Dolby
Two-
Channel
Encoder
Metadata
Figure A-1 Metadata Flow from Production to Consumer
In the simplest terms, there are two functional classifications of metadata:
Informational: These parameters convey information but do not affect either the
encoded bitstream or the decoding process. For example, the Bitstream Mode
parameter describes the audio service provided in the bitstream according to the
ATSC specification. This information may be used by certain components in the
audio system.
Control: These parameters direct how the decoder, encoder, or both process the
audio when certain modes are applied to the encoder or decoder. For example, the
Lowpass Filter parameter determines whether a lowpass filter is applied to the
main inputs of a Dolby Digital encoder, and the Surround Downmix Level
parameter instructs the Dolby Digital decoder how to mix the surround channels
during downmixing.